[Federal Register Volume 59, Number 213 (Friday, November 4, 1994)]
[Unknown Section]
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From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-26983]
Federal Register / Vol. 59, No. 213 / Friday, November 4, 1994 /
[[Page Unknown]]
[Federal Register: November 4, 1994]
VOL. 59, NO. 213
Friday, November 4, 1994
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 94-ANE-26; Amendment 39-9062; AD 94-22-12]
Airworthiness Directives; Hamilton Standard 14RF, 247F, 14SF, and
P6/5500/F Series Propellers
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to Hamilton Standard 14RF, 247F, 14SF, and 6/5500/F
(formerly Hamilton Standard/British Aerospace 6/5500/F) series
propellers, that currently requires initial and repetitive inspections
of the propeller control unit (PCU) servo ballscrew internal spline
(BIS) teeth for wear, and replacement, if necessary, of PCU servo BIS
assemblies. This amendment increases the repetitive inspection interval
from 500 to 1,500 hours time in service (TIS) since last inspection for
propellers that have a ballscrew quill damper installed. This amendment
is prompted by the availability of improved hardware that restricts
quill motion and enhances the lubrication of the BIS and significantly
reduces BIS wear. The actions specified by this AD are intended to
prevent inability to control the propeller blade angle due to tooth
wear in the PCU servo BIS assembly.
DATES: Effective December 5, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of December 5, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from Hamilton Standard, One Hamilton Road, Windsor Locks, CT
06096-1010. This information may be examined at the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
Counsel, 12 New England Executive Park, Burlington, MA 01803-5299; or
at the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Frank Walsh, Aerospace Engineer,
Boston Aircraft Certification Office, FAA, Engine and Propeller
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299;
telephone (617) 238-7158, fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 93-16-02,
Amendment 39-8659 (58 FR 44441, August 23, 1993), which is applicable
to Hamilton Standard 14RF, 247F, 14SF, and 6/5500/F (formerly Hamilton
Standard/British Aerospace 6/5500/F) series propellers, was published
in the Federal Register on May 27, 1994 (59 FR 27510). That action
proposed to increase the repetitive inspection interval from 500 to
1,500 hours time in service (TIS) since last inspection for propellers
that have a ballscrew quill damper installed.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Seven commenters concur with the rule as proposed.
One commenter concurs with the proposal to extend the repetitive
inspection interval from 500 to 1,500 hours TIS, but also states that
paragraph (a)(5) of the NPRM requires inspection at 1,500 hours TIS if
a damper is installed, but previously ``new'' PCU's were not required
to be inspected until 1,800 hours TIS since new. The commenter further
states that this interval is not consistent since it is a decrease of
300 hours with the improved hardware, and recommends the interval to be
extended to 1,800 hours TIS for new PCU's. The FAA concurs and has
revised this final rule accordingly.
The commenter also recommends the following changes to Appendix 1
of the NPRM:
The commenter states that the date of the damper installation
should not be required since those receiving a ``new'' PCU or one from
a repair station where the damper was installed may not have access to
the actual installation date. What should be required is an answer to
the question, ``Damper installed?'' (answer either ``Yes'' or ``No''),
and if ``Yes'', and the indication of whether it was installed ``at
this inspection'' or ``previously.'' The FAA concurs and has revised
this final rule accordingly.
The commenter states that the requirement to list the aircraft
model is not required provided the PCU part number is complete with the
dash or ``A'' number. The FAA concurs and has revised this final rule
accordingly.
The commenter states that blanks are not needed for the items
``Estimated Time on PCU'' and ``Actual Time on PCU.'' What is needed is
an indication as to which one of those statements applies to the
following: ``Time Since New (hours)'' and ``Time Since Last Ballscrew
Inspection/Repair (hours).'' The FAA concurs and has revised this final
rule accordingly.
The commenter states that there is no requirement to indicate (a
reminder to complete) completion of the ``pull check'' of the PCU quill
after it is reinstalled. The FAA concurs and has added this item to
Appendix 1 of this final rule.
Two commenters indicate that the installation of the damper had
merit and should reduce the PCU's vulnerability to wear. However, the
commenters believe that the inspection interval should not be extended
to 1,500 hours TIS for the following reasons:
The first commenter states that the root cause or single reason for
the ballscrew internal spline wear has not been identified. The
Original Equipment Manufacturer (OEM) bench test of the modified
ballscrew internal spline quill installation does not demonstrate a
test that duplicates actual operation; e.g., there is retaining wire
wear due to axial preload from the damper. Also, currently there is
inadequate scientific basis for reliance on the test data as there is
insufficient field experience data.
The second commenter also states that the specific cause of wear
has not been positively identified. The proposed modification does not
correct the negative failure modes in the PCU should a wear induced
failure occur. Finally, this commenter expresses concern that the field
data used to justify the increased inspection interval is being
collected only from a small percentage of units in operation.
The FAA does not concur with these comments. The FAA has researched
these issues and reviewed the data from numerous tests and
investigations that have been conducted to determine the cause of
extreme wear when it occurs on a very small number of splines in
service. The FAA has determined that by these tests and investigations
a number of factors contribute to how or if the spline joint will wear.
These factors include:
Magnitude and direction of vibratory environment.
How well the spline joint is lubricated.
Motion of elements within the joint due to stack up of clearances.
Thickness of chrome plating on spline teeth.
The FAA has therefore determined that there is no single factor for
wear of this complex joint. However, the major contributors of the
listed factors have been found to be lubrication and axial motion.
Laboratory tests and controlled field service data has proven the
damper reduces the wear factor by well over 20 times the rate before
its installation.
The retaining wire wear is not a phenomenon associated with the
damper introduction. The retaining wires generally show some degree of
marking (mainly dents in the wire) from the flat end of the ballscrew
spline teeth bearing on the round wire. This marking occurs on
retaining wires on PCU's with and without dampers installed. After an
initial ``Seating'' of the parts, the retaining wire continues to
operate without distress.
Currently, the FAA has reported data from high time controlled
field service units in multiple model installations to have accumulated
over 2,138 hours TIS with the same damper installed. In addition, the
damper modification has been available to operators since January 1,
1994. The manufacturer has shipped over 2,800 modification kits and has
conservatively estimated that over 300,000 hours of field time has been
logged by operators with the modification installed.
Based on the investigative reports, satisfactory field inspection
data, and improved wear factors resulting from the installed damper
modification, the FAA has determined that a negative failure mode
should not occur within the new inspection interval of 1,500 hours TIS.
The FAA has therefore adopted the inspection interval stated in the
NPRM.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 2,506 propellers of the affected design in
the worldwide fleet. The FAA estimates that 1,150 propellers installed
on aircraft of U.S. registry will be affected by this AD, that it will
take approximately 1.5 work hours per propeller to accomplish the
required actions, and that the average labor rate is $55 per work hour.
Based on these figures, and on the average utilization rate of 2,000
hours TIS per year equating to 4 inspections, the total cost impact of
the current AD per year on U.S. operators is estimated to be $379,500.
However, based on an average utilization rate of 2,000 hours TIS per
year, this superseding AD will eliminate 2.7 inspections per year per
propeller, resulting in an approximate yearly cost savings to U.S.
operators of $256,163.
The regulations adopted herein will not have substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government. Therefore, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a
significant economic impact, positive or negative, on a substantial
number of small entities under the criteria of the Regulatory
Flexibility Act. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air Transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
39.13 [Amended]
2. Section 39.13 is amended by removing Amendment 39-8659 (58 FR
44441, August 23, 1993) and by adding a new airworthiness directive,
Amendment 39-9062, to read as follows:
94-22-12 Hamilton Standard: Amendment 39-9062. Docket 94-ANE-26.
Supersedes AD 93-16-02, Amendment 39-8659.
Applicability: Hamilton Standard Models 14RF-9, 14RF-19, 14RF-
21, and 14RF-23; 247F-1; 14SF-5, 14SF-7, 14SF-11, 14SFL11, 14SF-15,
14SF-17, 14SF-19, 14SF-23; and 6/5500/F propellers installed on but
not limited to Embraer EMB-120 and EMB-120RT; SAAB-SCANIA SF340B;
Aerospatiale ATR42-100, ATR42-300, ATR42-320, ATR72, ATR72-210;
DeHavilland DHC-8-100 series, DHC-8-300; Construcciones Aeronauticas
SA (CASA) CN-235 and CN-235-100; Canadair CL215T and CL415; and
British Aerospace ATP airplanes.
Compliance: Required as indicated, unless accomplished
previously.
To prevent the inability to control the propeller blade angle
due to tooth wear in the propeller control unit (PCU) servo
ballscrew internal spline (BIS) assembly, accomplish the following:
(a) Inspect the PCU servo BIS assembly for tooth wear in
accordance with the Accomplishment Instructions of the following
Hamilton Standard Alert Service Bulletins (ASB), all dated April 7,
1994, as applicable: No. 14RF-9-61-A53, Revision 5; No. 14RF-19-61-
A25, Revision 4; No. 14RF-21-61-A38, Revision 4; No. 247F-61-A3,
Revision 3; No. 14SF-61-A59, Revision 4; and No. 6/5500/F-61-A11,
Revision 4; as follows:
(1) For a PCU with unknown time in service (TIS), and unknown
TIS since the last inspection, on the effective date of this
airworthiness directive (AD), and that does not have a ballscrew
quill damper installed, inspect within 200 hours TIS after the
effective date of this AD.
(2) For a PCU with 1,800 or more hours TIS or unknown TIS on the
effective date of this AD, and either has not been inspected, or has
been inspected more than 500 hours prior to the effective date of
this AD, in accordance with the applicable Hamilton Standard ASB
listed in paragraph (a) of this AD; and that does not have a
ballscrew quill damper installed; inspect within 200 hours TIS after
the effective date of this AD.
(3) For a PCU with 1,800 or more hours TIS or unknown TIS on the
effective date of this AD, and that has been inspected within the
previous 500 hours TIS in accordance with the applicable Hamilton
Standard ASB listed in paragraph (a) of this AD, and that does not
have a ballscrew quill damper installed, inspect within 500 hours
TIS since the last inspection in accordance with the applicable
Hamilton Standard ASB listed in paragraph (a) of this AD.
(4) For a PCU with less than 1,800 hours TIS on the effective
date of this AD, and that does not have a ballscrew quill damper
installed, inspect prior to accumulating 1,800 hours TIS, or within
300 hours TIS after the effective date of this AD, whichever occurs
later.
(5) For a PCU that has a ballscrew quill damper installed in
accordance with the following applicable Hamilton Standard Service
Bulletins (SB), or previous revisions: No. 14SF-61-67, Revision 2,
dated September 27, 1994; No. 14RF-9-61-61, Revision 1, dated
September 27, 1994; No. 14RF-19-61-29, Revision 2, dated September
27, 1994; No. 14RF-21-61-48, Revision 2, dated September 27, 1994;
No. 247F-61-6, Revision 2, dated September 27, 1994; and No. 6/5500/
F-61-19, Revision 2, dated September 27, 1994; inspect within 1,500
hours TIS since installation of the ballscrew quill damper.
(6) Thereafter, inspect at intervals described as follows:
(i) For propellers that have a ballscrew quill damper installed
in accordance with the applicable Hamilton Standard SB listed in
paragraph (a)(5) of this AD, or previous revisions, inspect at
intervals not to exceed 1,500 hours TIS since the last inspection
required by this AD.
(ii) For propellers that do not have a ballscrew quill damper
installed in accordance with the applicable Hamilton Standard SB
listed in paragraph (a)(5) of this AD, inspect at intervals not to
exceed 500 hours TIS since the last inspection required by this AD.
(7) If PCU servo BIS teeth are worn beyond the limits specified
in the Accomplishment Instructions of the applicable ASB's listed in
paragraph (a) of this AD, prior to further flight, replace the PCU
with a serviceable assembly in accordance with the Accomplishment
Instructions of the applicable ASB's listed in paragraph (a) of this
AD, and thereafter reinspect in accordance with paragraphs (a)(6)
and (a)(7) of this AD.
(b) Report the results of the initial and repetitive inspections
required by paragraph (a) of this AD by utilizing Appendix 1,
``Ballscrew Inspection Data,'' within 7 days of the inspection to
the Manager, Boston Aircraft Certification Office, Engine and
Propeller Directorate, Aircraft Certification Service, FAA, 12 New
England Executive Park, Burlington, MA 01803-5299; fax (617) 238-
7199. The reporting requirements of this AD terminate on December
31, 1995. Information collection requirements contained in this
regulation have been approved by the Office of Management and Budget
(OMB) under the provision of the Paperwork Reduction Act of 1980 (44
U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-
0056.
Appendix 1--Ballscrew Inspection Data
The following information must be reported and sent as soon as
possible but no later than 7 days after inspection to: Manager,
Boston Aircraft Certification Office, Engine and Propeller
Directorate, Aircraft Certification Service, Federal Aviation
Administration, 12 New England Executive Park, Burlington, MA 01803-
5299, Fax: (617) 238-7199.
Operator/Repair Station------------------------------------------------
Date of Inspection-----------------------------------------------------
PCU Part Number--------------------------------------------------------
PCU Serial Number------------------------------------------------------
Date Damper Installed--------------------------------------------------
Damper Installed (please circle one): YES NO
If ``YES,'' please circle one: This inspection Previously
Aircraft Serial Number-------------------------------------------------
Position (please check one): Left Engine______ Right Engine______
PCU Times (please circle one): Estimated Actual
Time Since New (Hours)-------------------------------------------------
Time Since Last Ballscrew Inspection/Repair (Hours)______
Inspection (please check one): Accepted______ *Rejected______
*Please indicate in comments if unit was rejected as part of the
functional check.
No. of left side teeth with steps______
No. of right side teeth with steps______
Comments:--------------------------------------------------------------
Ballscrew Quill Pull Check Completed (please circle one): YES NO
(c) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Boston Aircraft Certification
Office. The request should be forwarded through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, Boston Aircraft Certification Office.
Note: Information concerning the existence of approved
alternative method of compliance with this AD, if any, may be
obtained from the Boston Aircraft Certification Office.
(d) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the aircraft to a location where
the requirements of this AD can be accomplished.
(e) The requirements of this AD shall be done in accordance with
the following Hamilton Standard service documents:
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Document No. Pages Revision Date
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ASB No. 14RF-9-61-A53................................. 1 5............ April 7, 1994.
2-7 4............ March 1, 1994.
8 3............ July 28, 1993.
9 5............ April 7, 1994.
10-12 4............ March 1, 1994.
13 5............ April 7, 1994.
14-20 4............ March 1, 1994.
21 5............ April 7, 1994.
Total pages: 21
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SB No. 14RF-9-61-61................................... 1-2 1............ September 27, 1994.
3-10 Original..... December 9, 1993.
11 1............ September 27, 1994.
12-14 Original..... December 9, 1993.
Total pages: 14
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ASB No. 14RF-19-61-A25................................ 1 4............ April 7, 1994.
2-7 3............ March 1, 1994.
8 2............ July 28, 1993.
9 4............ April 7, 1994.
10 3............ March 1, 1994.
11 4............ April 7, 1994.
12-20 3............ March 1, 1994.
21 4............ April 7, 1994.
Total pages: 21
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SB No. 14RF-19-61-29.................................. 1 2............ September 27, 1994.
2 1............ May 6, 1994.
3-10 Original..... December 9, 1993.
11 2............ September 27, 1994.
12-13 Original..... December 9, 1993.
14 1............ May 6, 1994.
Total pages: 14
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ASB No. 14RF-21-61-A38................................ 1 4............ April 7, 1994.
2-7 3............ March 1, 1994.
8 2............ July 28, 1993.
9-10 4............ April 4, 1994.
11-20 3............ March 1, 1994.
21 4............ April 7, 1994.
Total pages: 21
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SB No. 14RF-21-61-48.................................. 1-4 2............ September 27, 1994.
5-10 Original..... December 9, 1993.
11 2............ September 27, 1994.
12-13 Original..... December 9, 1993.
14 1............ May 6, 1994.
Total pages: 14
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ASB No. 247F-61-A3.................................... 1 3............ April 7, 1994.
2-7 2............ March 1, 1994.
8 1............ July 28, 1993.
9-10 3............ April 7, 1994.
11-19 2............ March 1, 1994.
20 3............ April 7, 1994.
Total pages: 20
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SB No. 247F-61-6...................................... 1-4 2............ September 27, 1994.
5-10 Original..... December 9, 1993.
11 2............ September 27, 1994.
12-13 Original..... December 9, 1993.
14 1............ May 6, 1994.
Total pages: 14
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ASB No. 14SF-61-A59................................... 1 4............ April 7, 1994.
2-7 3............ March 1, 1994.
8 2............ July 28, 1993.
9-10 4............ April 7, 1994.
11-20 3............ March 1, 1994.
21 4............ April 7, 1994.
Total pages: 21
----------------------------------------------------------------------------------------------------------------
SB No. 14SF-61-67..................................... 1 2............ September 27, 1994.
2 1............ May 6, 1994.
3-9 Original..... December 9, 1993.
10 1............ May 6, 1994.
11 Original..... December 9, 1993.
12 2............ September 27, 1994.
13-15 Original..... December 9, 1993.
16 1............ May 6, 1994.
Total pages: 16
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ASB No. 6/5500/F-61-A11............................... 1 4............ April 7, 1994.
2-9 3............ March 1, 1994.
10-11 4............ April 7, 1994.
12 2............ July 28, 1993.
13 3............ March 1, 1994.
14 2............ July 28, 1993.
15-20 3............ March 1, 1994.
21 4............ April 7, 1994.
Total pages: 21
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SB No. 6/5500/F-61-19................................. 1 2............ September 27, 1994.
2 1............ May 6, 1994.
3-10 Original..... December 6, 1993.
11 2............ September 27, 1994.
12 Original..... December 6, 1993.
13-14 1............ May 6, 1994.
Total pages: 14
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This incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51. Copies may be obtained from Hamilton Standard, One Hamilton
Road, Windsor Locks, CT 06096-1010. Copies may be inspected at the
FAA, New England Region, Office of the Assistant Chief Counsel, 12
New England Executive Park, Burlington, MA; or at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(f) This amendment becomes effective on December 5, 1994.
Issued in Burlington, Massachusetts, on October 26, 1994.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 94-26983 Filed 11-3-94; 8:45 am]
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